"He knows that he made a poor decision that let our team down," Bucs coach Greg Schiano said.

Aqib Talib has been suspended for four games. (AP Photo)

Adderall is commonly used to treat Attention Deficit Disorder, but it can also be used a performance enhancing drug (it's an amphetamine), hence the NFL's mandate to not use the drug.

“Around the beginning of training camp, I made a mistake by taking an Adderall pill without a prescription,” Talib said in a statement released by the team. “This is especially regrettable because, for the past several months, with Coach Schiano’s help, I’ve worked very hard to improve myself—professionally and personally—as a player and a man. I am truly sorry to my teammates, coaches and Buccaneers fans, and I’m disappointed in myself. ... I have chosen to be immediately accountable for the situation I put myself in, which is why I will not exercise my appeal rights and will begin serving the suspension immediately.”